Mila said: "It hopefully resonates with men and women across the board but I think a lot of it has to do with achieving perfection which is inevitably impossible. There's no such thing.

"And so I think a lot of women want that, whether it's physical or mental, however they want it."

She said of her character Lily: "I think most of the film she's an interpretation of what Natalie's character sees her as. Which isn't always as nice as other people. It helps drive Natalie's character to achieve ultimately what she desires."

The Forgetting Sarah Marshall actress said her real-life friendship with Natalie and her admiration for director Darren Aronofsky made the film easy to make.

"It was great. It's always rare when you get to work with a friend of yours, so it was fun," she said. "I'm a huge fan (of Darren's), ever since I saw Pi. So it's been many, many years. To work with him is a huge honour."